ATmega325 Atmel Corporation, ATmega325 Datasheet - Page 183

• Manufacturer Part Number: ATmega325
• Manufacturer: Atmel Corporation

Specifications of ATmega325

• Flash (kbytes): 32 Kbytes
• Pin Count: 64
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 54
• Ext Interrupts: 17
• Usb Speed: No
• Usb Interface: No
• Spi: 2
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 2
• Eeprom (bytes): 1024
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8 to 5.5
• Operating Voltage (vcc): 1.8 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 3
• Output Compare Channels: 4
• Input Capture Channels: 1
• Pwm Channels: 4
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

2570N–AVR–05/11
• Bit 3 – USBSn: Stop Bit Select
This bit selects the number of stop bits to be inserted by the Transmitter. The Receiver ignores
this setting.
Table 20-10. USBS Bit Settings
• Bit 2:1 – UCSZn1:0: Character Size
The UCSZn1:0 bits combined with the UCSZn2 bit in UCSRnB sets the number of data bits
(Character SiZe) in a frame the Receiver and Transmitter use.
Table 20-11. UCSZ Bits Settings
• Bit 0 – UCPOLn: Clock Polarity
This bit is used for synchronous mode only. Write this bit to zero when asynchronous mode is
used. The UCPOLn bit sets the relationship between data output change and data input sample,
and the synchronous clock (XCK).
Table 20-12. UCPOL Bit Settings
UCPOLn
UCSZn2
0
0
0
0
1
1
1
1
0
1
USBSn
0
1
Transmitted Data Changed
(Output of TxD Pin)
Rising XCK Edge
Falling XCK Edge
UCSZn1
0
0
1
1
0
0
1
1
ATmega325/3250/645/6450
UCSZn0
0
1
0
1
0
1
0
1
Received Data Sampled
(Input on RxD Pin)
Falling XCK Edge
Rising XCK Edge
Stop Bit(s)
1-bit
2-bit
Character Size
5-bit
6-bit
7-bit
8-bit
Reserved
Reserved
Reserved
9-bit
183